SECAUCUS, N.J. — The Houston Astros had the No. 1 pick again, and this time, they took a pitcher polished beyond his years.

California high school left-hander Brady Aiken was the first selection in the Major League Baseball draft Thursday night.

"It's the most advanced high school pitcher I've ever seen in my entire career," Astros general manager Jeff Luhnow said. "He has command like I've never seen before of his stuff."

The 17-year-old from San Diego's Cathedral Catholic High School is just the third prep pitcher to be selected first overall, joining fellow lefties Brien Taylor (1991, Yankees) and David Clyde (1973, Rangers).

The Miami Marlins made it the first time high school pitchers were the top two picks in the draft when they selected Tyler Kolek, a hard-throwing right-hander from Shepherd High School in Texas.

Twenty pitchers were taken in the first round, tying the draft record set in 2001.

The Astros are the first team to select first in three consecutive drafts, having picked shortstop Carlos Correa in 2012 and right-hander Mark Appel last year. Aiken is in line to receive a huge contract. The allotted slot bonus for the top pick is nearly $8 million.

"Unbelievable. It's really a dream come true," Aiken said. "This is something that I've wanted ever since I was a young kid. I'm at a loss for words. This is my dream and it's finally starting to come true."

Aiken is also the first high school lefty to be drafted in the first five picks since Adam Loewen went fourth overall to Baltimore in 2002. The UCLA recruit, who compared himself to Clayton Kershaw and David Price, has terrific control of a fastball that hits 96-97 mph, a knee-buckling curve and a tough changeup that sits in the low- to mid-80s.

The 6-foot-5 Kolek has a fastball that sits in the high-90s and touched 100-102 mph several times, causing many to compare him to fellow Texas flamethrowers such as Nolan Ryan, Kerry Wood and Josh Beckett.

"How do you pass up a guy throwing 100?" Marlins manager Mike Redmond said after Miami's 11-6 win at Tampa Bay. "So, I'm happy with the pick. It's a big, old, country strong right-hander."

The Chicago White Sox selected North Carolina State left-hander Carlos Rodon with the third overall pick. The 6-3, 235-pound junior was widely regarded as the top college pitcher available and had been in the mix to go No. 1 overall. He followed a dominant sophomore year with a solid but not spectacular junior season.

Indiana slugger Kyle Schwarber went No. 4 overall to the Chicago Cubs as the first position player selected. He is a finalist for the Johnny Bench Award as the best catcher in Division I, although he could move to third base or the outfield in the pros.

"We'll let that play out," Cubs senior vice president of scouting and player development Jason McLeod said.

Nick Gordon, the son of former big league pitcher Tom Gordon and brother of Dodgers second baseman Dee Gordon, went fifth overall to Minnesota. The Florida high school slick-fielding shortstop was the first of the seven prospects in attendance at MLB Network Studios to have his name called by Commissioner Bud Selig, who is retiring in January and presiding over the draft for the final time.

After a few interviews, Gordon breathed a big sigh of relief and gave his father a huge hug.

"This is a proud moment. It's hard to describe," Tom Gordon said. "I have nothing but pride and pure joy for my boys."

Gordon, from Orlando's Olympia High School, also has some family bragging rights now: His father was a sixth-rounder by Kansas City in 1986, while his brother was a fourth-rounder by Los Angeles in 2008.

"We're pretty much the same player," Nick Gordon said of the brothers. "You know, he's got a little bit more speed than I do, I've got a little bit more pop than he does. But, you know, we model our game after each other."

A few other players followed in the footsteps of famous family members. Wichita State first baseman Casey Gillaspie went 20th overall to Tampa Bay, 17 spots ahead of where his brother Conor, the White Sox's third baseman, was picked in 2008.

"I can't really compare myself to him because he's in the big leagues," Casey said. "It was cool when it happened, but now I'm just ready and focused."

San Francisco outfielder Bradley Zimmer was taken 21st by Cleveland. His brother, Kyle, was the fifth overall pick by Kansas City in 2012. With the next pick, Detroit took California high school outfielder Derek Hill, whose father Orsino was a first-rounder in January 1982 and is now a scout for the Dodgers.

California high school catcher Alex Jackson went sixth to Seattle, which intends to move him to the outfield.

LSU righty Aaron Nola was the seventh overall selection by Philadelphia. Evansville lefty Kyle Freeland, a Colorado native, went No. 8 to the Rockies and said he's used to pitching in the thin Denver air and isn't afraid of it.

East Carolina right-hander Jeff Hoffman went ninth to Toronto, which also took Kennesaw State catcher Max Pentecost two picks later.

The New York Mets rounded out the top 10 picks by selecting Oregon State outfielder Michael Conforto.

In the year of Tommy John surgery in baseball, two pitchers who recently had the operation were selected in the first 18 picks — a sign that teams are confident in the success rate of the procedure. Even though they'll likely be sidelined for 12-18 months, Hoffman and UNLV righty Erick Fedde (No. 18 to Washington) remained attractive prospects.

Vanderbilt righty Tyler Beede was the 14th overall pick by San Francisco, becoming the 18th player in draft history to be selected in the first round of two June drafts. He went 21st to Toronto in 2011.

St. Louis wrapped up the first round of the draft, which is held over three days and 40 rounds, by selecting California high school righty Jack Flaherty at No. 34 — seven picks after taking Florida State right-hander Luke Weaver.